/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.metamodel.schema;

import java.io.Serializable;
import java.util.List;

import org.apache.metamodel.annotations.InterfaceStability;

/**
 * Represents a relationship between two tables where one set of columns is the
 * primary key, and another set is the foreign key.
 * 
 * @see Table
 * @see Column
 */
@InterfaceStability.Stable
public interface Relationship extends Serializable, Comparable<Relationship> {

	/**
	 * Gets the table of the primary key column(s).
	 * 
	 * @return the table of the primary key column(s).
	 */
	public Table getPrimaryTable();

	/**
	 * Gets the primary key columns of this relationship.
	 * 
	 * @return an array of primary key columns.
	 */
	public List<Column> getPrimaryColumns();

	/**
	 * Gets the table of the foreign key column(s).
	 * 
	 * @return the table of the foreign key column(s).
	 */
	public Table getForeignTable();

	/**
	 * Gets the foreign key columns of this relationship.
	 * 
	 * @return an array of foreign key columns.
	 */
	public List<Column> getForeignColumns();

	/**
	 * Determines whether this relationship contains a specific pair of columns
	 * 
	 * @param pkColumn
	 *            primary key column
	 * @param fkColumn
	 *            foreign key column
	 * @return true if this relation contains the specified primary and foreign
	 *         columns as a part of the relation
	 */
	public boolean containsColumnPair(Column pkColumn, Column fkColumn);

}